Lambert is a graduate transfer with two years of eligibility remaining and can play right away in the 2015 season.
The 6-foot-5, 220-pound Lambert was one of four team captains for the Cavaliers last season, when he threw for 1,632 yards with 10 touchdowns and 11 interceptions. He added two rushing touchdowns.
Lambert is a native of Jesup, Georgia. He played at Wayne County High School.
Georgia offensive coordinator Brian Schottenheimer said the interest in Lambert does not reflect displeasure with the other quarterbacks' performance this spring.
"I think obviously it speaks to the fact that we're trying to create competition,'' Schottenheimer said Wednesday before Lambert announced his decision. "... Unfortunately, injuries are part of the process. It doesn't matter whether it's quarterback or offensive line, we're trying to create competition. We think that leads to guys raising their level of play and raising the standard. That's what we're trying to do.''
When asked Wednesday if one of the three returning quarterbacks could handle the starting job, Schottenheimer said: "I think so.''
"I saw a lot of positives with all of them through the spring,'' Schottenheimer said. "Our consistency needs to be better. That's to be expected when you're putting in a new offense. I think if those guys continue to make the strides they made ... heading into fall camp, I feel like we'll have a guy who can go out there and help us win a lot of football games and hopefully compete and win a SEC championship.''
Before choosing Georgia, Lambert visited Florida on Monday, a source told ESPN.
Lambert and former Notre Dame quarterback Everett Golson, another graduate transfer, both visited Georgia and Florida. However, Golson did not meet SEC bylaws to transfer to an SEC school, and league commissioner Greg Sankey would not grant Golson a waiver, sources said. Ultimately Golson transferred to Florida State.
ESPN.com's Brett McMurphy and Matt Fortuna and The Associated Press contributed to this report.